anchor near pump nozzle

Dear all,

In case if we place an anchor very close to pump nozzle. All forces and moments are carried by the anchor except the very big axial force. However, it's just calculation. In real world, can we ignore this problem? I have heard from my senior stress engineer in my company that if like that we can ignore pump nozzle evaluation.

Hope to hear your all opinion.

Regards,

You are placing an 'anchor' close to a pump, presumably to remove moments. So how stiff is the anchor really ? Is it a trunnion for instance ? Local deflections could well mean that the 'anchor' is actually doing nothing.

If the anchor is very stiff and the trapped expansion between it and the pump is anything significant, your pump bearings or coupling will surely fail.

Anchor before pump nozzle ( If intend to use) is generally used for cooling water pump where temperature effect is very minimum. we have previously used anchor on Leg support for basket type strainer. Small lateral flexibility of strainer ( Or trunnion) may take care of axial expansion of pipe piece in between pump nozzle & anchor location.

Regards

Habib

MoverZ is right as pump bearings and couplings are more liable to failure when anchors are placed close to nozzle than if you have a flexible piping connections at nozzle without anchors.

Always remember that bearings have millimeters of clearance and once piping moves; either the housing or the bearing get close to each other..they strike and start heating up. Alignment of such pumps also create problems and lots of re-work.

The way I see it is: do your calculations/stress models as per Standards imply which will in turn provide you to go for a "conservative approach". The only difference of application of all these norms and standards is: some may be too close or some may be too far from this conservative approach but both would be safe.

As your software/calculation gives u high axial force than reduce this axial force by doing whatever you can (remove anchors for instance). Your piping will be more flexible and nozzle loads will be much less [in reality] and your equipment/piping will have much longer life than predicted by the same Standard. Instead of risking the reputation of your company or decreasing the life of dynamic equipment in your project you should consider not placing them at nozzles.

Our Standards do say to consider all the dynamic & transient effects of fluids in the piping but mostly they are ignored in calculations. Once you put them in calculations you will see that providing anchors might solve one problem only but create many more.

If you really want to put anchors than place expansion joints or hangers in between them and nozzles.

""""If you really want to put anchors than place expansion joints or hangers in between them and nozzles.""""

Hi Salz

I agree Expansion joint may be placed in between anchor & nozzle. We even place Tied expansion joint in cooling water line.

I don't understand how hangers will help in similar situation???


Regards

Habib